Convoluted excavation method for undermined tunnel with extra-large cross section

Abstract

The invention discloses a convoluted excavation method for an undermined tunnel with an extra-large cross section, which comprises the following steps of: a, excavating a right side small pilot tunnel; b, excavating a transverse channel; c, excavating a left side horizontal upper pilot tunnel; d, performing multistep expanding excavation on a middle lower pilot tunnel; e, excavating an inverted arch and core soil; and f, constructing a secondary lining of the large cross section of the tunnel. Compared with the conventional tunnel excavation method, the convoluted excavation method for the undermined tunnel with the extra-large cross section has the advantages that: the small pilot tunnel climbs and is divided into a plurality of parts to be excavated when a small cross section is abruptly changed into the large cross section, so that the safety risk of excavating the large cross section at one time is reduced, and the problem of traffic organization in the tunnel subjected to single-head advancing is solved by a circuitous folding mode; back break during excavation is effectively controlled, the using amount of various materials is saved, and the time consumption and the wastage rate of mechanical equipment are reduced; and compared with the conventional center diaphragm (CD) and double-side-wall excavation methods, the method is easy to operate, good in cross section excavation effect, quick in excavation progress and high in safety performance.

Description

technical field [0001] The invention relates to an engineering construction method, in particular to a method for rotary excavation of an extra-large cross-section underground excavation tunnel. Background technique [0002] For large-section tunnels located in the center of downtown and shallow buried and underground excavated, safe construction is the key point. The CD method of ordinary excavation of extra-large cross-section underground excavation tunnel is to divide the large section into left and right side walls and carry out the excavation in sections to complete the excavation of the left side wall to form the left side support and the temporary support of the middle partition wall. There are still great safety hazards in the construction of the single side wall, and it is easy to cause bias when there is a building above it. At the same time, one side wall is used as a construction channel, and it is inconvenient for vehicles to enter and exit. [0003] Ordinary e...

AI Technical Summary

Problems solved by technology

[0004] Construction of tunnels with shallow burial and underground excavation with super large sections and many buildings above, conventional methods are limited in terms of construction safety, construction progress, and traffic organization in the tunnel

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